1. Field of the Invention
This invention relates to the heating of material by use of microwave energy. More particularly, this invention relates to rendering a material like meat products and blood by the use of microwave energy.
2. Description of the Prior Art
The prior art has seen the development of many types of apparatus for heating materials and has seen the development of many types of processes for rendering of meat products and the like. There have even been numerous patents on the use of microwave energy in the precooking of food products and the like. Typical are the following U.S. Pat. Nos.: 3,321,314; 3,614,365; and 3,961,568 describe the use of microwave energy for precooking meats such as bacon. Other patents such as U.S. Pat. Nos. 3,805,009; 3,881,403; 3,908,029; 3,872,603; and 3,916,136 describe apparatus for the use of microwave energy for cooking materials such as donuts, causing bread to rise, drying moist pasta, drying moisture laden materials and employing standing waves in a cavity with quartz rollers and the like. Others such as U.S. Pat. Nos. 3,725,628 and 3,885,118 describe technical apparatus with energy suppression means to lower the energy loss of the microwave energy during use of the apparatus.
From the foregoing, it can be seen that this art has become crowded. Despite the crowded nature, there has not been a totally satisfactory and efficient method and apparatus for employing microwave energy for rendering or other processes in which the material possesses a large amount of water. Apparently the separated water interfered with the efficiency of the microwave energy. Also, the microwave energy in standing wave fashion has created intense hot spots in large chambers or the like. Because of the inefficiencies and disadvantages of the prior art methods and apparatus, other heating steps, such as with steam, were incorporated into the processes to try to keep down the cost; and it was considered infeasible to use only microwave energy for large scale processes, such as rendering.